Lacaille

Lacaille, fully Nicolas-Louis de Lacaille (often written La Caille) (1713–1762), was a French astronomer noted for his rigorous study of the southern sky and for producing one of the first comprehensive star catalogs of that region. Born in Paris, he studied mathematics and astronomy and later worked at the Observatoire de Paris.

A key phase of his career was his voyage to the Cape of Good Hope (1751–1752) to observe the southern heavens and to catalog stars not visible from Europe. Using the instruments of his time, he systematically measured positions and magnitudes, compiling thousands of stars. He published his major work, Coelum Australe Stelliferum, posthumously in 1763, which presented detailed charts of the southern sky and served as a foundational reference for southern astronomy.

Lacaille is also known for reorganizing the constellation Argo Navis, splitting it into three smaller constellations: Carina, Puppis, and Vela. In addition, he introduced 14 new southern constellations and standardized many star names and coordinates, expanding European understanding of the southern celestial sphere. His catalog and methods contributed to the accuracy and scope of celestial mapping during the 18th century.

Legacy and honors from his work include the naming of a lunar crater Lacaille in his honor. Lacaille’s efforts provided a crucial bridge between early celestial cartography and modern astronomy, particularly in mapping the southern sky that had been largely uncharted by European observers. He died in Paris in 1762 at the age of 48.